Abstract
Zinc oxide sinters were impregnated with several kinds of metallic salts in aqueous solutions to give different potential barrier at intergranular contacts of the oxide particles. Measurements on conductance change of these samples at 120°C, which takes place on introduction of 112 to air, revealed that chemical properties of metallic salts rather than the potential barrier play an important role in appearence of the conductance change. However, when the conductance change appeared it was accompanied with an appreciable change in the potential barrier height. There were remarkable differences in the degree of the conductance change among several n-type semiconducting oxides which were impregnated with the most active PdCl2. Reldtive height of electronic energy levels of these oxides seems to have some relation to the observed phenomenon. It was confirmed from studies on TiO2 samples of different conAuctivity that the conductance change is greatly influenced by conductivity of samples measured in air and was large for samples of low conductivity.
